Interlocking Kelly bars (also called as interlocking bars) are generally suitable for hard soils conditions, such as cobbles, rocks, etc. We are now capable of manufacturing 3-element, 4-element and 5-element interlocking Kelly bars, among which 5-element interlocking Kelly bar is firstly manufactured by domestic manufacturer. With the most mature manufacturing technology, 5-element interlocking Kelly bar has been successfully applied for XCMG550, TR550, SWDM520, XCMG400, TR460, XCMG360, SWDM360